A conventional umbrella includes a top rib having a cross section of U shape for pivotally connecting a stretcher rib. The U-shaped top rib is generally made of steel material to increase the total weight of the umbrella, thereby being heavy and inconvenient for carrying. Some umbrella ribs are made of steel material to have a cross section of circular or "O" shape of the rib, still being heavy in weight and inconvenient for carrying.
If the umbrella ribs are made of light materials such as aluminum alloy, the umbrella weight can be reduced for convenient carrying. However, the aluminum ribs are lacking of resilience and can not well resist the deformation, twisting or bending of the ribs.
The present inventor has found the drawbacks of the conventional umbrella ribs and invented the present rib assembly having light grooved rib reinforced with resilient rib.